Self Sealing Membrane Question

I have a somewhat "weird" question about the (Grace, etc.) self sealing membranes. How large diameter holes are "self sealing"? I figure nail holes are ok, maybe even screw holes. How about 1/4 inch diameter bullet holes? Thinking about a way to do a somewhat self-sealing backstop for a small indoor shooting range.

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Self Sealing Membrane Question

Indoor range backstops are typically either a slanted steel plate which ricochets the bullet downwards into a sand trap or a containment system of sand bags, ground up rubber tires, or other materials. Basically, I woke up in the middle of the night with a thought of using a replaceable board covered with a self sealing membrane in front of a sand bag trap to catch the bullets and contain the sand. The slanted steel plate/sand box trap can let dust into the air. The sandbags contain everything until they are strained to recover the bullet fragments, or they break.

Self Sealing Membrane Question

Where would this range be located? Your basement or garage? I can't imagine anywhere in the U.S. that you could legally do that. I've been a competitive pistol shooter for more than 25 years, and know of some commercial indoor ranges that shut down because the cost to upgrade just their ventilation system to comply with newer dust and lead abatement rules was prohibitively expensive. If you did this and were caught, today's eco-Nazis would probably have your house declared a Superfund site.

Self Sealing Membrane Question

Thats a sales pitch. I assume you are referring to the peel and stick SBS based ice dams materials that are put at the eaves, valleys and other areas. They seal somewhat around the shaft of a roofing nail, but the shaft of the nail stays there, unlike a Bullet which would blow right through the material and probably cut a wad out of it.

As a roofing Bitumen, Coal Tar pitch was sold as being self healing due to its 140 degree softening point, but your range wont be up on the roof where it gets hot as Hades, where pitch melts.

My dad had a device that looked like a square funnel with a circular area in the back. The slug would hit the side of the funnel and deflect into and spin around in the circular trap in the back.

Pretty cool device. I think it was made of 1/4 inch steel plate.

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